Coal conveyor



5 Sheets-Sheet 1 INVENTOR O. A. SMITH COAL CONVEYOR July 4, 1961 Filed OCT.. 2l, 1957 July 4, 1961 o. A. SMITH 2,990,942

COAL coNvEYoR Filed Oct. 2l, 1957 3 Sheets-Sheet 2 INVENTOR BY u/MMK ATTORNEY July 4, 1961 o. A. SMITH 2,990,942

COAL CCNVEYOR Filed Oct. 2l. 1957 5 Sheets-Sheet 3 INVENTOR A'TORNEY United States Patent 2,990,942 ICOAL CONVEYOR Owen A. Smith, 1819 IEmerson Ave. S., Minneapolis, Minn. Filed Oct. 21, 1957, Ser. No. 691,236 8 Claims. (Cl. 198-214) in a trough at the bottom of the bin into which the coal may drop by gravity. If the conveyor extends entirely across the bin so as to be able to convey the coal even when the bin is almost empty, the screw conveyor is subjected to tremendous strain `when the bin is full due to the weight of the coal and due to the large amount of coal in the conveyor. If, on the other hand, the conveyor extends only a short distance into the bin, coal must be moved manually into the conveyor when the bin is partially empty.

A feature of the present invention resides in the provision of a coal conveyor including a screw type conveyor element which is rotatably mounted in a tubular enclosure having a slotted upper extremity to permit fuel to enter. Covers are mounted to close the upper portion of the tubular enclosure throughout most of the length of the conveyor so as to allow a restricted area beneath the pile of coal through which the coal may drop into the interior of the conveyor enclosure. These covers are arranged in longitudinally spaced sections and each section is individually removable. As a result, more and more of the covers may be removed asv the size of the coal pile decreases thereby gradually permitting the coal to enter the enclosure as less and less of the conveyor is covered.

l A feature of the present invention resides in the fact that the covers are provided with handles secured thereto toextend in'a direction toward the outlet end of the conveyor; rThese handles are designed to extend from the pile of coal to be accessible before a section of the cover is `exposed` By grabbing this handle and properly operating the cover, the cover may be removed from beneath the edge ofthe pile Vof coal thus opening this portion of the 'conveyor enclosure and permitting additional coal to drop into the conveyor.

`f A 'further feature of the present invention residesin th'e'provision/of 'a conveyor having a series of' removablel Acovers which are supported in spaced relation so as toprovide "spaced openings beneath the pileof coal through which aismall amount of coal may flowrat all times vv'vherr'the corresponding part of the conveyor e'nclosure is-beneaththe pile of coal. As a result, there was Valways aloadfupon the outer end of the conveyorv and sorne coal: is`always in motion beneath the pile of coal sol asto provide a more uniformload upon the screw CQnYe-YQL i l fItis therefore afeature of the present invention to provide'a means of metering or regulating the amount of coal available for the screw conveyor to pick up. As a result,

the conveyor I nay be employed in coal bins where the coal' is substantiallyrnore `than live feet Vin depth without dan-` ger that the weight of the coal upon the screw conveyor will not cause the conveyor to Ifeed more than its rated ca-4 "fAfurther 'feature of the present invention reside-sin pacityand so that the conveyor will not jam up in any part ofthe conveyor enclosure. i

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the provision of a screw conveyor including conveyor portions which are varied in pitch and in diameter so as to provide an even ow of coal in the auger housing. The conveyor is so constructed as to provide short sections of large diameter screw conveyor alternated with smaller diameter sections thereof. The conveyor enclosure is provided at points spaced throughout its length with connecting bridges which span the slot in the top of the enclosure and act to hold the enclosure from spreading. i The large diameter portions of the conveyor are positioned inwardly of these bridging portion so that the screw conveyor is held centered in the housing and prevents Vcoal from building upon the bottom of the conveyor housing as would be possible if the conveyor wasnot properly centered therein.

A further feature of the present invention resides in the fact that the screw conveyor or auger is so constructed that it may be removed even though it is buried beneath a pile of coal. The yconveyor is made in more than one section so connected that the drive end can be disengaged from the remainder of the conveyor and the main body of the conveyor may be pulled from its enclosure even though it is beneath a large pile of coal. The auger may be lrep-aired and replaced by inserting it and rotating it so as to screw the auger into whatever coal is within the enclosure.

A feature of the present invention resides in the provision of a novel form of separable joint which permits two parts of the auger to be easily detached. The abutting ends of the auger sections are provided with axial sockets, one of which anchors a pin of stainless steel or the like. This pin engages in the socket in the other part of the auger. radially and abut together; This arrangement provides a continuous and unbroken ight, as compared with other structures in which the flight ends are overlapped. A

' flat steel strip is Welded or otherwise secured to one flight to project beyond the radial edge* thereof. This strip overlaps the abutting portion of the adjoining ilight and the parts may be held together by means of a bolt of stainless steel or the like. Thus, the sections ofthe auger are held in proper alignment and are held for rotationin unison.

A further feature of the `present invention resides in the provision of an obstruction removal plate at the location where the auger enters the coal bin wall. The open top v of the auger housing ,extends beneath this plate and the plate mayV bejremoved for the separation of any foreign material from the coal. Throughout the major portion of the length of the conveyor, the channel-shaped covers and the channel-shaped clean out plate provide ya passage through which elongated foreign materials may passv without jamming the conveyor.

, An added feature of thepresent invention resides inv the fact that the conveyor is provided with a 4reverse flight at its extremity which prevents the'coal from being forced against the transfer case. As a result the coal builds up inheight in the end of the transfer vcase and normally Adrops by gravity into the feed hopper.

vA further feature of `the 4present invention resides. in the provision of a thrustand pull bearingof 'hard wood at the drive end of the auger which has been impregnated in paraffin and which is capable of resisting very material Vforce and Wear and not damaged by coal dust.- Other porous materials, such as porous bronze, may be similarly impregnated with a lubricant and employed.. l `Still another feature of the present invention vresides ini the provision of anroverll switch above the transfer case and hopper so that in the event the stoker drive shall fail to operate properly, the yhopper'will not continuefto ll up through continued movement ofthe conveyor'.

These and other objects and novel features of the presi The flights of the auger sections are cut ent .invention will be more `clearly and .fully kset forth .in the following specification and claims.

In the drawings forming a part of the specification:

FIGURE l is Aa side elevational view of the coal Vconveyor showing the general arrangement thereof.

. FIGURE 2 is a vertical sectional lView through the conveyor, the conveyor screw or auger being shown in full lines.

FIGURE 3 is a sectional view throughthe transfer case and coal hopper showing a typical installation where V:the conveyor is on the same plane-as the stoker.

FIGURE 4 is asectional view through a portion of the conveyor enclosure, the position of the sectionbeing indicated by the linesf4-*4 of-FIGURE .1. FIGURES is an enlarged sectional view showing the removable obstruction removal plate near the end Vof the conveyor enclosure.`

FIGURE 6 is a top plan view of .the structure rshown in FIGURE 5, a portion vof the wall being illustrated in section.

FIGURE 7 is a vertical section through the transfer case and bearing supportingtheend of the conveyor screw or auger.

FIGURE-8 is a side elevational view of a joint between two auger sections.

FIGURE 9 is a view similar to FIGURE 8 .showing the two sections in separated condition.

FIGURE l is a view'similar to FIGURE 8 showing il a slightly modified form of construction.

. FIGURE 11 is an enlarged sectional view showing the connection between one ofthe removable covers and the means for holding the cover in place.

.FIGURE 12 is a sectional viewon the line l12-12 of FIGURE 1.

Conveyors of the type in question are capable of being mounted in various positions `to suit different` installations. For example, in some instances the stoker .is mounted below the level of the oor of the coal bin. In such a case the coal conveyor may feed directly into-the top or side of the stoker hopper. In the present case, both the stoker and the conveyor are mounted on a common level and a transfer case is attached to the hopper to deliver the coal thereto from the end ofthe conveyor.

As is indicated in the drawings the conveyor includes an elongated hollow tubular enclosure 10 which is provided with a slot or opening 11 at its upper extremity. This opening extends throughout the length of the main portion of the tubular 'enclosure .10. Inverted U-shaped angle members 12 form bridging connections between opposite sides of the slot 111 at intervals throughout the length thereof. These angle members 12 include a top portion 13 and downwardly extending side 'anges 14 which are welded or otherwise Asecured to the tubular member 10 on opposite sides of the slot 11.

As is indicated in FIGURE 4 'of the drawings, the elongated tubular enclosure 10 is provided witha transversely extending foot portion 1-5 which is welded to theenclosure to extend transversely thereof. These feet, which are shown connected to the tubular enclosure 10 at the point 16 .hold the enclosure with the slot 14 uppermost.

. A large portion of the top of the yconveyor enclosure is normally closed by a .series of removable covers 17. Eachcover 17 comprises a body of channel 'shaped section which is arranged with the base of the channel uppermost. Asis evident from FIGURE 4 of the drawings, each cover 17 includes a top panel 19 and downwardly projecting flanges 20 on opposite edges thereof. Means are provided for holding the covers 17 in their proper location. This means includes short angle brackets 21 secured to the lianges 20 near` one end thereof. and shaped to lit in surface contact with the outersurface of the tubular enclosure 10. Brackets A22 having ends 23 which are olset lfrom the surface of the enclosure 10 are welded to thisenc'losure, these bracketsbeing onopposite sides of the slot 11 and arranged in properly spaced relation d' member 17 is provided with a projecting strip 24 which is welded to the cover member 117 at 25. As is indicated in FIGURE l2 of the drawings, this strip 24 is designed to extend into the bridging member 12 to ,properly 'locate the cover member with respect to the conveyor enclosure. A handle 26 is welded or otherwise secured to each ofthe cover members 17 to extend upwardly from the top panel 19 and preferably inclined toward theoutlet end of the conveyor. The covers may bemanipulated Vby operation of the handles 26. The cover vmembers are i mounted upon the conveyor at a time when no coal overlies the portion ofthe conveyor being covered and each cover member is applied by placing it in position to bridge the slot 11 of the conveyor enclosure 10 between `a pair 0f spaced bridge members 12 and then pulling thecover member toward the outlet lend ofthe conveyor to `engage the strip 24 beneath the bridging member 12 and to engage the angular clips 21 beneath the offset ends 23 of lth brackets 22.

It will be noted from an examination of FIGURE l of the drawings that the cover members 17 do not extend the full distance between the spaced bridging ymembers 12 thereby providing apertures at intervals throughout the length of the conveyor. Due to the restricted size of `these apertures, the amount of coal which will flow therethrough is limited and will not place an undue burden upon the auger. At the same time, the conveyor is operating at all times vto some extent throughout its length thus equalizing the strain upon the screw conveyor.

The conveyor enclosure 10 usually extends through a i wall 29 of the coal bin and into the Stoker room. A

sleeve 130 telescopes over the end of the enclosure 10 and is welded thereto as indicated at 431. The tubular member 30 is provided with a slot 32 through the major portion of its length forming a continuation of the slot 11. However, the extremity of the sleeve 30 as indicated at 33 is completely tubular and accommodates the end of a hollow cylindrical enclosure continuation 34. The continuation 34 is secured in place within the cylindrical end of the sleeve 30 by means of bolts 35 or other suitable connecting means.

As is indicated in FIGURES 5 and 6 of the drawings, an inverted channel-shaped member 36 overlies -the portion of the enclosure 10 which extends through the wall 29 forming a continuation of the enclosures formed by the various removable covers and the bridging members 12. A removable inspection door 37 is provided which is somewhat similar in nature to the covers 17. The member 37 comprises a channel shaped element with its base uppermost and extends in abutting relation to the channel 36 to overlie the slot 32 in the sleeve 30. A

bolt 39 or other fastening means extends through the base of the channel G7 and into a nut 40 which is welded or otherwise secured to the sleeve 33. 'I'he channel member 67 is provided with an end closure 41 shaped to fit the curvature of the sleeve 33 and at its opposite ends includ a projecting strip 42 which is welded or otherwise secured at 43 to the base of the channel 37 and which projects into the end of the channel 36. This strip 42 holds the two in alignment but permits removal of the channel 37 when the bolt 39 is removed.

The end structure of the conveyor enclosure is best illustrated in FIGURE 7 of the drawings. The hollow sleeve 34 extends into a transfer case 44 which is attached to the Stoker hopper in a manner which will be later described. A pair of steel discs 45 confine a wooden bearing disc 46 which is impregnated with ya lubricant such as parafn or the like. The discs and plates are held in. place by retaining pins 47 Y or other suitable means and an oil cup 49 may be provided exteriorly of the Wooden disc to permit added lubricant to be applied. Other porous material capable of being impregnated with a lubricant may be used in place of wood.

,The screw conveyor or auger is indicated in general by the numeral 50 and includes a conveyor shaft 5K1 which extends through the discs 45 and 46 axially thereof. The end .of the shaft 51 is provided with a collar 52 which is notched to engage the end of a cooperable coupling member 53 driven by suitable drive mechanism within the power transmission 54. Preferably, the conveyor is formed inmore than one section andthe conveyor section whichis within the transfer case 44 includes a reverse night portion 55 which is spaced from the end of the forward flight portion 56. The manner in which the conveyor Sections are connected together is indicated in FIGURES 8 and 9 of the drawings. Asis indicated in these tigure's, the sections of the shaft 51 which are to` t together are both socketed, one end including a socket 52 and the other end including a socket 53. A pin 54 of stainless steel or the like is wedged in one socket suchas B and engages in the other socket 52 with a running fit.

' The4 ends of the two conveyor flights terminatel along radial planes 55 through the axis of the shaft 51 and the flight of one section abuts against the liight of the other section when the two parts are engaged.A A metal strip 56 is welded to the back side of one iiight and isdesigned to overlap'a portion of the adjoining iiight. By abutting the ght ends, a continuous flight is provided, differing from structures in which the ends of the ight; sections are overlapped. As all of the longitudinal strain upon the .conveyor tends to pull the conveyor to the yright as viewed in the drawings, the conveyor sectionsare held from separation by the strip 56. However, if any added insurance against separation or relative rotation between the .two parts is desired, a bolt 57 may extend through the projecting end of the strip 56 and through the iiight of the conveyor which it overlaps.

As is best indicated in Figure 2 of the drawings, the conveyor 50 varies in pitch and in diameter throughout its length, and is usually provided with a large diameter portion 59 which is enclosed within the sleeve 30 and within the portion of the conveyor enclosure which extends through the wall 29. The portion of the conveyor between the wall 29 and the closest bridging member is 12 is shown as being of small diameter but a larger diameter portion 60 is provided inwardly of the first bridging portion 12. Similar enlarged diameter portions 61, 62 and 63 are shown lying inwardly of the various bridging members 12. The purpose of this arrangement is to provide a good bearing for the conveyor at the points where the conveyor enclosure is strongest. Obviously, the conveyor enclosure is strongest at the points where the slot 11 is bridged by the bridging members 12 and accordingly the larger diameter portions 60, 61, 62 63 are inwardly of the various bridge members while the intermediate portions 64, 65 and 66 of the conveyor are of smaller diameter. This arrangement prevents the jamming of the conveyor as the coal is carried throughout the length thereof while the larger diameter conveyor portions tend to prevent any build-up of coal wiithin the conveyor, by preventing the auger from getting off center.

With reference now to Figure 3 of the drawings, the transfer case 44 is shown as connected to the stoker hopper 67. The stoker hopper 67 is usually provided with tapering lower sides 69 and 70 which slope toward the stoker conveyor 71. Normally the stoker Iis provided with upwardly extending sides 72 to permi ta supply of fuel to be placed in the hopper. One of the sides 72 of the hopper is cut away and the sloping wall 69 is connected to the upper edge of the sloping wall 73 of the transfer case 44. The outer wall 74 of the transfer case is provided with an upward continuation '75 which ex1A tends to theheight of the side wall 72 and is connected' to an extension of the end 76 of the hopper.

Means-is provided for stopping the operation of the conveyor 50 when the hopper tends to overiill. Fo'r 'example, if the feed screw 71 of the stoker should fail to function properly, and the conveyor screw 50 continues' to operate, the hopper would naturally overiiow. .This is prevented by the use of a plate 77 which is hingedly connected at 79 to the transfer plate walls 75 and which supports a junction box 80 including a mercury switch 81. f The mercury switch 81 is normally in a positionto make the circuit to the conveyor motor which operates thef transmission case 54.Y The mercury tube 81 is preferably curved with the ends of the tube lower than the center to provide a differential between stop .and start. Minor.

agitation of the plate 77 will therefore not actuate the switch. However, in the event the hopper tends to overlill,` Vthe coal bears against the undersurface of the plate 77, tilting this plate upwardly. As this actiontakes place, the mercury switch `81 is tilted to an extent sutiicient to break the circuit to the conveyor motor until the level of coal in the hopper has decreased.

I-t is believed that the operation of the` apparatus Vcanf*r be easily understood from the description already given.

After the conveyor is installed the various covers 17 are put into place to be held in place by the angle clips 21 andthe projecting strips 24. Each cover abuts a bridging member 12 leavingV an opening between the other end such as is indicated by the dotted line and the level of coal in the pile gradually drops until the handle 26 of.

the cover exposed. Y v

At this point, the handle 26 may be grasped and the first cover may be removed thus increasing the space available for the coal to drop nearest the outlet end of the conveyor. The angle which the coal assumes remains substantially constant. As the coal is gradually used, the covers are removed one at a time until the coal in the bin is substantially depleted or the bin is again relled.

In accordance with the patent statues, I have described the principles of construction and operation of my improvement in coal conveyors, and While I have endeavored to set forth the best embodiment thereof, I desire to have it understood that changes may be made within the scope of the following claims without departing from the spirit of my invention.

I claim:

l. A stoker conveyor including an elongated tubular enclosure having a product receiving slot extending longitudinally thereof, a series of covers overlying said slot, respective means normally holding the ends of each cover in proper spaced relation overlying said slot, both of said respective holding means for each cover acting in a direction to prevent lateral displacement thereof and one of said holding means acting to prevent longitudinal displacement in one direction whereby each of said covers is individually removable when manually shifted in an opposite longitudinal direction, and a screw conveyor extending through said enclosure.

2. A conveyor structure including an elongated tubular enclosure having a longitudinally extending product receiving slot in its upper surface, a series of bridging members bridging said slot at spaced intervals longitudinally of said enclosure, a series of covers overlying said slot between said bridging members, said covers being shorter than the distance between said bridging members to provide product receiving apertures between said covers, cooperable means on said enclosure and on said covers for releasably holding said covers in tixed position overlying 17 nearest the outlet end of the conveyor `is has been inserted in the bin the coal may said slot, and a screw conveyor in said enclosure having portions thereof closely adjacent both the upper and lower surfaces ofsaid enclosure.

3. The construction described in claim 2 and including cooperable means between said covers and said bridging members for assisting in holding said covers in proper relation overlying said slot.

4. The construction described in claim 2 and in which saidscrew conveyor includes large diameter portions of slightly smaller diameter than the interior of said tubular enclosure and intermediate smaller diameter portions, said large diameter portions being located inwardly of said bridging members and relatively close thereto and said smaller diameter portions being `in a spaced relation beneath said covers and also in a spaced relation above the bottom of said tubular enclosure.

5. The construction described in claim 2 and in which said bridging members are channel shaped in cross section and are secured with the bases of the channels uppermost and the sides of the channel extending downwardly into contact with said enclosure on opposite sides of said slot, and in which said covers are similarly shaped in cross section, one end of each cover having a projecting member for underlying a bridging memberto releasably anchor said one end in place, said cooperable means being near the other end of each cover.

6. The construction described in claim 5 and including a handle on each of said covers extending upwardly therefrom at a locus near said one end and angled toward the outlet end of the conveyor.

7. A conveyor for use in conjunction with a coal bin and a Stoker, said conveyor including an elongated tubular enclosure supported on the base of the coal bin and extending through the coal bin wall, said enclosure having a slot in its upper surface through which coal may pass, a series of bridging members connecting opposite sides of said slot `in said enclosure at spaced intervals longitudinally thereof, said bridging members being suband overlying said slot, cooperable means on said covers and .said enclosure for normally holding said covers in a longitudinally spaced relation tosaid enclosure, said last named means being disengageable to permit removal of said covers, a channel-shaped member of similar cross section to said bridging members overlying the portion of said 'conveyor extending through said wall, and an inspection ,cover overlying said enclosure on the side of the wall opposite from the coal bin, said inspection cover being Vof a cross section similar to said bridging members and ,secured in an overlying relationship with the end of saidslot.

8. A conveyor structure including an elongated tubular enclosure :having a longitudinally extending product receiving slot in Yits upper surface, a series of covers overlying said slot, means for maintaining said covers in an individually releasable and longitudinally spaced relationship, and a 'screw conveyor comprising large diameter portions of slightly smaller diameter than the interior of said tubular enclosure and intermediate smaller diameter portions, saidsmaller diameter portions underlying the slot openings formed by the longitudinal spacing of vsaid covers and being disposed above the bottom of said tubular enclosure.

v References Cited in the le of this patent UNITED STATES PATENTS 1,785,287 Ryan et al Dec. 16, 1930 1,867,573 Leach July 19, 1932 `2,038,471 vBenatar Apr. 2l, 1936 2,131,305 Shaw Sept. 27, 1938 2,225,215 Guthrie Dec. 17, 1940 2,369,370 Scholl Feb. 13, 1945 2,815,852 Harrer Dec. l0, 1957 

